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A Sentiment analyzer tells you if a text it’s positive or negative. For example “I love the new Mad Max Fury road” (positive) or “i am not impressed by the bike” (negative). The Sentiment classifier hosted by uClassify is very popular so I decided to spend some time on improving it.

The goal was to improve the classification accuracy, especially for short texts such as Twitter messages, Facebook statuses or other snippets while maintaining high quality results on texts with more information.

The old Sentiment classifier was built by 40k amazon product reviews. The straight forward way to improve a classifier is to add more data. Thanks to the Internet we were able to find multiple data sources we could train our classifier on. In fact it’s now trained on 2.8 million documents!

The results are good very good, the accuracy on large documents (reviews) went from about 75% to 83%. Tweets went from 63% to about 77%.

As a part of the uClassify upgrade I’ve recompiled the local server for 64-bit. This was necessary since I’m working on a huge classifier for sentiment and needed the corpus tool to be able to handle more then what 32-bit pointers could hold.

If you are running a local uClassify server, you can download the 64-bit (and 32-bit) here. The 64-bit server is already used in production for uClassify and should be pretty well tested by now.

The old uClassify site has been set to read-only and the database & classifier migration has been done. Now we are just waiting for the DNS to propagate over the nets before the new site can be taken into use. This time on an elastic IP so hopefully this we won’t have to do anymore of those ‘waiting’ operations in the future.

Exciting times! I’ve decided to push the next update out on Thursday May the 14th (2015). Normally you won’t notice updates but this one is huge.

I’m migrating servers from old ‘Classic’ Amazon EC2 to their new cloudy thing. This will require a DNS update which takes time to propagate over internet before it’s completely done.

Read Only Mode during the transition

Since this also involves a database migration step, I will set the uClassify to ‘read-only’ until it’s done. This means that all the read calls (classify etc) should continue to work during the transition while write calls won’t go through (creating, training classifiers). You won’t be able to register as a new user during this time either. DNS updates usually takes about 48h.

What will be new

First, I’ve done extensive testing to make sure the API will behave exactly the same. If I have not missed anything your app will continue to work without any changes.

The major ‘visible’ changes are:

– A new responsive bootstrap UI (the vanilla theme, somehow cosmetics always ends up last on my prio lists

– To make it more secure the entire site will be in SSL (don’t worry all the API links without https:// will still work).

– It will be possible to sign in via Twitter, Facebook and Google.

– You can train classifiers by uploading files.

This is the first of a few major updates for uClassify, it doesn’t introduce much new cool fancy stuff but it’s a very important updates that paves the road for the stuff I actually want to add, such as an JSON api.

If you have any questions please don’t hesitate to contact me. (contact AT uclassify DOT com)

Lately uClassify has gotten a lot of attention and the user community has grown at a faster rate. We are getting more requests and inquires from our customers and it feels like machine learning is something that many people know of, not only the tech savvy geeks

Whats in the next update

For a couple of months now I’ve been reworking the both the front end and back end to make it easier to go forward. It feels like a necessity to get some of the tech up to date. After all the tech is at least six years old.

The site will be replaced with a modern bootstrap powered front end. Making it much more responsive and easy to maintain. There will also be a few new features in the first release, e.g. ability to upload files to train classifiers. It will also be possible to log in via Google, Twitter and Facebook.

The backend is also being reworked to make it easier to work with. Those changes will be completely invisible to users and all public APIs will remain the same.

I hope to have all of this done before the end of June 2015.

Future plans

– Once all the new code is in place and the service is up and running I intend to add a complete JSON Api for the service. E.g. right now you need to use XML for batching calls.

– Open source C# and Java libs for calling the API.

– Add more and better classifiers. Today it’s easier to find good training data for classifiers.

– Classifier performance, I’ve a few ideas of how to improve the accuracy of the classifier further.

uClassify has been around since October 2008, and to date has almost 15000 registered users and nearly 2000 classifiers. All this time the web api has been completely free with no restrictions what so ever (number of calls, classifiers, size of classifiers etc). But lately we have gotten a lot more traffic over our web api. This is of course a lot of fun but it also adds more server cost. Therefore I want to try to introduce payment options for those who can pay but keep it free for the majority of users.

Free, Indie, Professional and Enterprise Accounts

What I want to do is to introduce a pricing model that doesn’t affect the majority of users and hopefully only affects those who can afford to pay.

After analyzing the logs I’ve found only a few percent of the users make more than 1000 calls per day. Therefore I decided to introduce a limit of max 5000 calls per day for free accounts. Keeping in mind that I want it affordable for everyone I introduced both ‘Indie’ and ‘Professional’ accounts. Both with a cap of 100.000 calls per day. The indie account is for smaller companies (<100.000€ yearly revenue). The pricing for an Indie account is initially set to 9€/month and for professional 99€/month.

On top of that there is an option to upgrade to 1.000.000 calls / day for a price of 299€/month for high end users. Also I will offer a free Academic account with 1.000.000 calls / day cap for researchers.

What will happen to existing accounts?

If you already have a uClassify account it will be upgraded to an Enterprise account with X months expiry time. All of those who are likely to be affected will be emailed with a heads up. But most of you won’t notice this change.

The system will likely be implemented during the nearest weeks.

I am open to suggestions, if you have feedback or think this sucks please let me know! (contact AT uclassify DOT com)

Lately we have been getting a lot requests to our sentiment classifier, many are from social media analyst companies. In fact our sentiment analysis is now the most popular classifier at uClassify!

I just wanted to share something that could be usable for you guys. By using our latest Api call, ‘classifyKeywords’ you can see which keywords are the strongest triggers for the positive and negative classes. This could reveal additional valuable information for your clients.

For example, if you use the keyword analysis on a long product review, you could use the keywords to extract the sentences where the product is mentioned in a positive or negative way. Why not highlight it in green or red? Highlighting sentences will give a very good overview for human reviewers.

Here is how an XML request looks like (just swap ‘classify’ for ‘classifyKeywords’):

The response will be in XML or alternatively JSON. You can classify a text or let uClassify download an URL for you and classify the content (optionally with or without the HTML).

When to use the URL API
– Want to get up and running quickly
– Low volumes of classifications (can be slow on many requests at once)
– Each text is only run through one classifier (otherwise you should batch with XML API)
– If you only is interested in classifying and not training or other fancy features.

XML API

With the XML API you can do everything. You can create classifiers, train them, classify, extract keywords and more. Another important feature is that you can batch calls. This means that you can get thousands of, say, tweets or blog posts, classified in one single request as long as the request string is less than 1 MB.

Local Server

As a final option you can run a local classification server. This is for users who have huge amounts of data to process.

The API is pretty much the same as the XML API except that no authentication is needed.

When to use a local classification server
– You have huge amounts of data to process
– CPU performance is very important (you don’t have to share CPU cycles with other uClassify users)
– Install the server in your own data centre, to avoid any network lag to uclassify.com
– Have full control over the server

With the keywords API you can extract relevant/discriminating words from texts, this opens up a lot of possibilities for developers. Keywords can be used to for tag clouds and answer questions such as why a text is classified into a class. Compared to ordinary tag clouds they bring an extra angle as they are not the overall keywords but only for a certain genre. For example you can find out what parts of a text makes it manly using the gender classifier at the same time running it through the mood classifier and finding out keywords that indicate happy parts.

After having tested the keyword API for a while I’ve just made it public in the XML API now. It works exactly like the classify API but you will get back a list of keywords for each class as well.

I’m currently working on a new keywords API for uClassify. This will allow users to get information about what words that are good discriminators for certain classes. To test this API I spent last weekend to built a visualization application for urlai.com.

Here is a screenshot how the visualization prototype show data:

I would very much like to get some feedback on this, you can try it here, please comment below.